IF you're cropped bps are the same size like
front 300x200, side 800x200, top 800x300
you should make all of them the same size (800x800) WITHOUT scaling but you should use the canvas size tool instead.
IF the side is 1000x300 and front 150x150, you must use the imagesize tool. (make sure the with-height balance is remained.)
for all those without photoshop, you can use irfanview or photofiltre
http://www.photofiltre.com photofiltre also has an autocrop function.